package top.saiyin.list;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

/**
 * @Program: leetcode
 * @Description: 两数之和
 * @Author: sy
 * @Create: 2020-08-27
 **/
public class TwoSum {

    public static void main(String[] args) {
        int[] nums = {2, 7, 11, 15};
        int target = 9;
        System.out.println(Arrays.toString(twoSum(nums, target)));
    }

    public static int[] twoSum(int[] nums, int target) {
        Map<Integer, Integer> map = new HashMap<>();
        for (int i = 0; i < nums.length; i++) {
            int complement = target - nums[i];
            if (map.containsKey(complement)) {
                return new int[]{map.get(complement), i};
            }
            map.put(nums[i], i);
        }
        throw new IllegalArgumentException("No two sum solution");
    }
}
